The second great derivation claim in the Goetia, after Bael and Baal, is that Astaroth descends from Astarte, and it is on firmer ground than the first, though it is still not settled.
The Hebrew Bible uses Ashtoret, and the plural Ashtarot, for the goddess worshipped by Israel's neighbours, and the plural form is what the demon's name most closely resembles. The goddess herself is very well attested: Ugaritic Athtart, Phoenician and Punic Astarte, and behind them the Mesopotamian Ishtar. Her cult is documented archaeologically and epigraphically across the Levant over more than a thousand years.
The route from goddess to demon is also documented in outline. Christian and Jewish polemic against surrounding cults regularly demoted foreign deities to demons, and Astaroth appears as a demon in Christian sources well before Weyer. So the philological resemblance and the historical mechanism are both present.
What is missing is the middle. No text shows the transition happening for this name in the way the Baal-zebul transition can be shown. The demon Astaroth of the grimoires is male, appears riding a dragon with a viper in hand, has foul breath, and discourses on the fall of the spirits, and none of that connects to a goddess of love and war in any traceable way except the name. The masculinity in particular is unexplained, and attempts to explain it as a deliberate degradation are speculation.
The scholarly position is that the derivation is plausible, widely accepted, and not demonstrated. It should be reported that way rather than as a fact, and readers should be alert that the confidence with which it is usually asserted is not matched by the evidence for it.